Ryan, Ai.gar, and O'Connell — Syntheses of Some New Dyes. 87 



The chemotherapeutic properties of the following dyes of the benzidine series 

 have been examined : — 



Naga-rcd (Benzidine coupled with /3-naphthyIamine-3-G-disulphonic 



acid) . 

 Trijpan-vcd (Benzidine - mono - sulphonic acid coupled with /3- 



naphthylamine-3-6-disulphonic acid) . 

 Trypan-Uuc (Tolidine coupled with amido-H-salt). 



Trypan-rcd was tested by Vassel (Comptes Eendus de la Soc. de Biol., 62 

 (1907), p. 414), and recognized as effective in the treatment of diseases due to 

 Spirilla ; and Manteufel (Arbeiteu aus dem Kaiserlichen Gesundheitsamt, 29, 

 No. 2) also recognized the beneficial effect of benzidine dyes. Mesnil's trypan- 

 violet has also been employed in addition to his trypan-blue. An investigation 

 of the chemotherapeutic properties of the dyes mentioned in this paper is at 

 present in progress. 



Experimental Part. 



Tetrazotisation of Benzidine- Sidplione-Disidphonic Acid. 



A solution of 20'3 grams of benzidine-sulphone-disulphonic acid in 

 150 c.cs. of water containing 20 c.cs. of concentrated hydrochloric acid was 

 cooled with ice to 5°C. 15 c.cs. of concentrated hydrochloric acid were 

 added, and the solution tetrazotised by slowly adding, a few drops at a time, 

 a solution of 7'2 grams of sodium nitrite in a little water. The tetrazo 

 solution was stirred vigorously aud the nitrite added until it gave a slight 

 reaction with starch-iodide paper. 



1. Coupling of Benzidine-Sulphone-Disidplionic Acid with Naphthionic Acid. 



NH 2 SOsNa S0 3 Na NH= 



l_ _1 I 



N = N— / ^ / \— N = fj— /\/\ 



\_/ \_/ I I I 



\ so,/ Y X/ 



S0 3 Na 



The tetrazotised solution mentioned above was poured into a cold 

 concentrated solution of 75 grams of sodium naphthionate (a large excess to 

 obtain a better yield), and the mixture was stirred mechanically for two days. 

 After the first half-hour's stirring, a solution of 35 grams of sodium carbonate 

 was added, a few drops at a time, so that the whole was used up by the end 

 of the second day. Next day the colouring matter was heated to 80° C., and 

 the mixture saturated with common salt. The colouring matter, which 

 separated on cooling, was filtered and dried. The mass was purified for analysis 



[if 2] 



